If there are pets that have been living with you for the longest time, I bet its a dog. As for me, we have a family dog that is older than! My brother and sisters also are owners of dogs that are more than years old. I myself own two Giant English mastiffs that are both 10 years old. They are Prince and Princess. I can't rename them to King and Queen even though they already have a daughter, Awie. It is because two of my chinchillas are named Chinnie King and Chinnie Queen haha.
Before when I introduced new pets in my house, I can feel that my two dogs are jealous. They always walk around the new pets like they are investigating or scanning the wholeness of the new intruder to their territory. My dogs are to sharing the house with my two cats but not with a rabbit and chinchillas. I really wanted them to get along peacefully so I did a lot of things just to have them like each other.
I took them to the basement, of which, they are all unfamiliar with. Since all of them are unfamiliar with the place, they behave like they are newcomers and just sit and stay in one place. The chinchillas and the rabbit with their natural behavior as playful, did the work. They sniffed the dogs and the cats, play with their tails, run back and forth in front of them. Eventually the cats stood up and played along with the rabbit. For the dogs, it took more than an hour before they felt home with the newcomers. After a few minutes of playing, I gave them treats so that they will know that I like it when they are playing, and that playing with each other is good.
From then on, in any part of the house, they would play and I can really see how they like each other. Its just a matter of introducing a new pet to your old one in a manner that is not forced. Just let them have their animal instincts working, you will see the great results.
